TOEFL Listening: ETS-TOEFL听力机经 - IERW5N81F61_PQ3OP$

How does the professor organize the lecture? A. By describing a relatively new scientific discipline, then explaining how it began B. By describing deep-sea biological sounds, then comparing them with geological sounds C. By describing some deep-sea sounds, then discussing the challenge of identifying their source D. By defining interdisciplinary research, then giving an extended example of how it works